Criminal Minds Finale: Who's The Replicator? And Who Will Die?

The BAU's season-long stalker, who's been duplicating the team's closed cases, will finally be revealed on Wednesday's two-hour Season 8 finale (9/8c, CBS), but fans already have a wild guess as to who the group's tormenter is.

, but can Luke Skywalker do this?" executive producer Erica Messer jokes to TVGuide.com. Hamill — who, lest we forget, voices The Joker on the animated Batman series — plays John Curtis, a highly intelligent man who specializes in biochemistry. How he figures into the BAU picture, Messer won't say, but his science know-how will "come into play in the last two episodes."Viewers will only have to wait until the final minutes of the first episode though to learn The Replicator's identity when he kidnaps one of the team members, which will lead to the death of a "major" character at his hands. Promos show Blake (Jeanne Tripplehorn) chained to a chair, but surely CBS wouldn't spoil it if she were the death too, right? "[The kidnapping] part is solved, let's put it that way," Messer says. However, it's not a coincidence that it's Blake who winds up in The Replicator's lair."He's not just taking whoever he gets his hands on first or anything. He has a very detailed plan, as you can tell from everything he's done this year," Messer says. "Introducing a hero in Alex Blake in our premiere and introducing The Replicator at the end of that episode was not a happy accident. It was all meant to weave together. We've given a lot of clues throughout the year as to who he is. I think the identity of who he is will make sense. You'll see the pieces of the puzzle we put together and if you go back and watch this season, you'll be able to see how we dropped clues here and there about him."

As for the "major" death, it will be another copycat kill — of the case the BAU solves in the first hour. That episode features the return of Hotch's (Thomas Gibson) brother Sean (Eric Johnson), whom we last saw way back in Season 1 when he headed to New York to be a chef. Sean's still in the Big Apple, but might be cooking something else other than food: He calls Hotch, who's visiting his girlfriend Beth (Bellamy Young) with Jack (Cade Owen) in the city, for help when he gets caught up in a string of deaths caused by a meth/ecstasy cocktail nicknamed "Doctor Death." "The further the team investigates, the further they find out his involvement," Messer says. "It gives you a little glimpse of the journey of two brothers and how some things never change despite the years and lessons learned. ... It ends on a bittersweet, but hopeful note."Unlike last season's finale, among a few others, this year's closer was not structured as a two-parter, but was tweaked to be as such when CBS scheduled the final two hours on the same night. "We actually hoped that they would be separated by a week because the end of [Episode] 23 is such a great cliff-hanger, which we always planned on happening," Messer says. "It'd be great if you had to wait all week for the conclusion for that, but it's all good. I think it's proven to be a good thing for them to do a two-hour finale."

Something else that changed thanks to CBS: The season won't end on a cliff-hanger. "The more we talked about it, not just internally in the writers' room, but with our partners at CBS and ABC [Studios, the production company], everybody preferred that we not do a cliff-hanger this year," Messer says, adding that this preceded the protracted Season 9 negotiations. "We didn't have one last year and it worked well, and I think this one does too."Still, that doesn't mean it's case closed with The Replicator."You're not entirely sure if The Replicator's gone," she warns. "But for the most part, it's wrapped up."Criminal Minds airs Wednesdays at 9/8c on CBS. Who do you think will die?(Full disclosure: TVGuide.com is owned by a joint venture between Lionsgate and CBS.)